#include<iostream>
#include<string>
#include<vector>
#include<cctype>
using namespace std;

vector<char> tran(const string & );


vector<char>  tran(const string& s)
{
    vector<char>  s1;
    for(string::iterator iter = s.begin();iter != s.end();iter++) //实现大小写转换
    {
        if(islower(*iter))
            *iter = toupper(*iter);
        else
            *iter = tolower(*iter);
    }
    string::iterator mid,left,right;//定义中值，
    mid = (s.end() - s.begin() ) /2;
    left = s.begin();
    right = mid;
    for(;right != s.end();right ++)
    {
        s1.push_back(*right);
        if(left != mid)
        {
            s1.push_back(*left);
            left++;
        }
    }
    vector<char>  s2;
    for(string::iterator it = s1.end()-1;it >= s1.begin();it--)
    {
        s2.push_back(*it);
    }
    return s2;
}

int main()
{
    string s;

    while(cin>>s)
    {
        string s1=tran(s);
       cout<<s1<<endl;
    }
    return 0;
}
